The hammer for driving nail-like fasteners goes back in history to timeless eras of the past and has basically remained unchanged through the years in its basic form. Recent discoveries of hammer heads dating to the bronze age bear a striking resemblance to modern day hammers. Of course, specialized hammers have been developed for special purposes, e.g., upholstery hammers, framing hammers, roofing hammers, chipping hammers and the like but they all have the basic attributes of a weighted head, a fastener driving surface and a convenient handle at right angles with respect to the head and generally parallel to the fastener driving surface.
In recent years there has developed wide acceptance for pneumatically driven fasteners such as nails and staples and in such case, the hammering device may take on the appearance of a stapler, a handgun or specialized shapes for this specialized form of fasteners.
The use of pneumatic powered fastener driving devices has always presented a problem of requiring a pneumatic gas supply under pressure which is usually provided by an air compressor, storage tank and hose line to the driving device. Also, pressure regulators and valves are necessitated for an effective pneumatic driving device.
I have been familiar with the various types of manual and pneumatic fastener drivers and have seen the various types of fasteners used (i.e., nails, screws, staples, etc.). One important advantage of the pneumatic device is that with a continuous source of pneumatic pressure, fastening can be in a virtually continuous basis as when a magazine is included in the tool capable of storing quantities of fasteners. Typically, manual hammers have not provided for multiple fasteners storage and feeding. Also, conventional hammers with the exception of magnetic head tack hammers seldom have the capability of holding the fastener prior to nailing.
In the roofing operation for residences, the hammer must drive a large headed roofing nail through a sheet of sub roofing and one or more thicknesses of wood or composition roof shingles. The nail must be driven straight, leaving no visible bump through the next succeeding layer and must enter a hold well in a somewhat resilient (unbacked by framing at most locations) surface.
In my study of fastener driving needs, I have encountered one additional particularly troublesome operation, namely, the driving of drywall nails into paper covered plaster-like (Gypsum) construction board used for interiors of residences and some commercial structures and commonly referred to as drywall or sheetrock.
Drywall commonly comes in 4'.times.10' or 4'.times.12' sheets which must be placed and held in place while being secured, including overhead to the ceilings. The number of fasteners required to attach a single sheet of sheetrock can be as many as 60. Additionally, each drywall nail has a cupped head so as not to penetrate through the drywall paper covering and must be dimpled when it is set. By dimpling it is meant in the trade that the cupped head, for example, is driven below the outer surface of the drywall compressing the exposed paper without destroying its integrity with only a hole the size of the shank of the nail penetrating the plaster-like body of the drywall. The dimple must be broader than the head and may be as large as 1" to 11/2" in diameter. After the drywall nail has been driven, a further surface treatment step of troweling on a surface compound to fill the dimpling to the level of the uncompressed drywall surface must be accomplished. A material commonly referred to as surfacing compound or "mud" adheres well to the paper surface and covers the head of the drywall nail.
Recently, there has been a trend toward the use of threaded or drywall screws which have a lesser tendency to "pop" when the underlying wood dries or moves after the drywall surface has been placed and finished. Drywall screws, however, are expensive-much more so than the most common drywall nail and considering the fact that a multitude of fasteners are needed for a single sheet of sheetrock of the interior of the residence, using the more expensive drywall screws can have a significant cost impact.
I viewed this state of the art as one which presents a very real need for a self contained hammer which does not require any pneumatic source, which does hold each individual nail for driving, and which does hold a supply of nails and automatically feeds each nail so that no handling of each individual nail is required. I also recognized the need that such a hammer can be a boon to roofers, carpenters in general and, particularly, the drywall installer if it can meet their particular requirements.
In virtually all non-powdered fastener settings with the exception of staples, nail magazines, or nail holders have not met tradesmen's acceptance.
I have reviewed the prior art found in searching and the following illustrate prior attempts to improve hammers.
______________________________________ 293,516 A. POTTER 02/12/1884 362,224 N. NEWMAN 05/03/1887 917,291 M. HAMMER 04/06/09 932,211 W. WIELAND 08/24/09 1,488,161 C. MCCORMICK 03/25/24 2,113,084 J. HEWITT 04/05/38 2,193,143 L. RAPIEN 03/12/40 2,238,983 J. ABRAHAMSEN 03/08/66 2,667,639 E. SCHICK 02/02/54 2,893,279 P. HASKELL 07/07/59 3,180,550 I. BOYNTON 04/27/65 3,602,419 M. DOBERNE 08/31/71 4,341,336 G. SMITH 07/27/82 4,434,929 N. KEENER 03/06/84 4,448,339 R. PETTIGREW 05/15/84 4,566,619 E. KLEINHOLZ 01/28/86 4,611,739 D. ROWTON 09/16/86 4,676,424 A. MEADOR 06/30/87 4,714,186 R. WILLIAMSON 12/22/87 4,742,875 J. BELL 05/10/88 4,796,495 A. SCHAR 01/10/89 4,831,901 A. KINNE 05/23/89 4,838,471 D. CHIESA 06/13/89 ______________________________________